After the American Revolution established the United States, northern states, beginning with Pennsylvania in 1780, passed legislation during the next two decades abolishing slavery, sometimes by gradual emancipation. Massachusetts ratified a constitution that declared all men equal; freedom suits challenging slavery based on this principle brought an end to slavery in the state. In other states, such as Virginia, similar declarations of rights were interpreted by the courts as not applicable to Africans. During the following decades, the abolitionist movement grew in northern states, and Congress regulated the expansion of slavery in new states admitted to the union. David Brion Davis argues that the main driving force was a new moral consciousness, with an intellectual assist from the Enlightenment, and a powerful impulse from religious Quakers and evangelicals. Christian evangelicals identified slave ownership and complicity as a grave sin – one that had to be purged from the world.[2]

In 1315, Louis X, king of France, published a decree proclaiming that "France signifies freedom" and that any slave setting foot on the French ground should be freed. This prompted subsequent governments to circumscribe slavery in the overseas colonies.[4]

Some cases of African slaves freed by setting foot on the French soil were recorded such as this example of a Norman slave merchant who tried to sell slaves in Bordeaux in 1571. He was arrested and his slaves were freed according to a declaration of the Parlement of Guyenne which stated that slavery was intolerable in France.[5] Born into slavery in Saint Domingue, Thomas-Alexandre Dumas became free when his father brought him to France in 1776.

Louis XIV's Code Noir regulated the slave trade and institution in the colonies. It gave unparalleled rights to slaves. It includes the right to marry, to gather publicly or to take Sundays off. Although the Code Noir authorized and codified cruel corporal punishment against slaves under certain conditions, it forbade slave owners to torture them or to separate families. It also forced the owners to instruct them in the Catholic faith, implying that Africans were human beings endowed with a soul, a fact that was not evident until then. It resulted in a far higher percentage of blacks being free in 1830 (13.2% in Louisiana compared to 0.8% in Mississippi.[6]) They were on average exceptionally literate, with a significant number of them owning businesses, properties and even slaves.[7][8] While some other free people of color, such as Julien Raimond, spoke against slavery.

The Code Noir also forbade interracial marriages, but it was often ignored in French colonial society and the mulattoes became an intermediate caste between whites and blacks, while in the English colonies mulattoes and blacks were considerated equal and discriminated against equally.[8][9]

The revolt of slaves in the largest Caribbean French colony of Saint-Domingue in 1791 was the beginning of what became the Haïtian Revolution led by Toussaint L'Ouverture. Rebellion swept through the north of the island, and many whites and free people of color were killed, as well as slaves. Slavery was first abolished in 1793 in St. Domingue by Sonthonax, a French Commissioner sent by the Convention in order to safeguard the allegiance of the population to revolutionary France.

The Convention, the first elected Assembly of the First Republic (1792–1804), on 4 February 1794, under the leadership of Maximilien Robespierre, abolished slavery in law in France and its colonies. Abbé Grégoire and the Society of the Friends of the Blacks were part of the abolitionist movement, which had laid important groundwork in building anti-slavery sentiment in the metropole. The first article of the law stated that "Slavery was abolished" in the French colonies, while the second article stated that "slave-owners would be indemnified" with financial compensation for the value of their slaves. The French constitution passed in 1795 included in the declaration of the Rights of Man that slavery was abolished.

During the French Revolutionary Wars, French slave-owners massively joined the counter-revolution and, through the Whitehall Accord, they threatened to move the French Caribbean colonies under British control, as Great Britain still allowed slavery. Fearing secession from these islands, successfully lobbied by planters and concerned about revenues from the West Indies, Napoleon Bonaparte decided to re-establish slavery after becoming First Consul. He promulgated the law of 20 May 1802 and sent military governors and troops to the colonies to impose it. On 10 May 1802, Colonel Delgrès launched a rebellion in Guadeloupe against Napoleon's representative, General Richepanse. The rebellion was repressed, and slavery was re-established. The news of this event sparked another wave of rebellion in Saint-Domingue. Although from 1802, Napoleon sent more than 20,000 troops to the island, two-thirds died mostly due to yellow fever. He withdrew the remaining 7,000 troops and slaves achieved an independent republic they called Haïti in 1804. Seeing the failure of the Saint-Domingue expedition, in 1803 Napoleon decided to sell the Louisiana Territory to the United States. The French governments initially refused to recognise Haiti. It forced the nation to pay a substantial amount of reparations (which it could ill afford) for losses during the revolution and did not recognise its government until 1825.

On 27 April 1848, under the Second Republic (1848–52), the decree-law of Schœlcher abolished slavery in the remaining colonies. The state bought the slaves from the colons (white colonists; Békés in Creole), and then freed them.

At about the same time, France started colonising Africa and gained possession of much of West Africa by 1900. In 1905, the French abolished slavery in most of French West Africa. The French also attempted to abolish Tuareg slavery following the Kaocen Revolt. In the region of the Sahel, slavery has however long persisted.

Passed on 10 May 2001, the Taubira law officially acknowledges slavery and the Atlantic Slave Trade as a crime against humanity. 10 May was chosen as the day dedicated to recognition of the crime of slavery.

Lord Mansfield (1705–1793), whose opinion in Somerset's Case (1772) was widely taken to have held that there was no basis in law for slavery in England.

The last known form of enforced servitude of adults (villeinage) had disappeared in England by the beginning of the 17th century. In a 1569 court case involving Cartwright, who had bought a slave from Russia, the court ruled that English law could not recognize slavery, as it was never established officially. This ruling was overshadowed by later developments. It was upheld in 1700 by the Lord Chief Justice John Holt when he ruled that a slave became free as soon as he arrived in England.[10]

In addition to English colonists importing slaves to the North American colonies, by the 18th century, traders began to import slaves from Africa, India and East Asia (where they were trading) to London and Edinburgh to work as personal servants. Men who migrated to the North American colonies often took their East Indian slaves or servants with them, as East Indians have been documented in colonial records.[11][12]

Some of the first freedom suits, court cases in the British Isles to challenge the legality of slavery, took place in Scotland in 1755 and 1769. The cases were Montgomery v. Sheddan (1755) and Spens v. Dalrymple (1769). Each of the slaves had been baptized in Scotland and challenged the legality of slavery. They set the precedent of legal procedure in British courts that would later lead to successful outcomes for the plaintiffs. In these cases, deaths of the plaintiff and defendant, respectively, brought an end before court decisions.[13]

African slaves were not bought or sold in London but were brought by masters from other areas. Together with people from other nations, especially non-Christian, Africans were considered foreigners, not able to be English subjects. At the time, England had no naturalization procedure. The African slaves' legal status was unclear until 1772 and Somersett's Case, when the fugitive slave James Somersett forced a decision by the courts. Somersett had escaped, and his master, Charles Steuart, had him captured and imprisoned on board a ship, intending to ship him to Jamaica to be resold into slavery. While in London, Somersett had been baptized; three godparents issued a writ of habeas corpus. As a result, Lord Mansfield, Chief Justice of the Court of the King's Bench, had to judge whether Somersett's abduction was lawful or not under English Common Law. No legislation had ever been passed to establish slavery in England. The case received national attention, and five advocates supported the action on behalf of Somersett.

In his judgment of 22 June 1772, Mansfield declared:

The state of slavery is of such a nature that it is incapable of being introduced on any reasons, moral or political, but only by positive law, which preserves its force long after the reasons, occasions, and time itself from whence it was created, is erased from memory. It is so odious, that nothing can be suffered to support it, but positive law. Whatever inconveniences, therefore, may follow from a decision, I cannot say this case is allowed or approved by the law of England; and therefore the black must be discharged.[14]

Although the exact legal implications of the judgement are unclear when analysed by lawyers, the judgement was generally taken at the time to have determined that slavery did not exist under English common law and was thus prohibited in England.[15] The decision did not apply to the British overseas territories; by then, for example, the American colonies had established slavery by positive laws.[16] Somersett's case became a significant part of the common law of slavery in the English-speaking world and it helped launch the movement to abolish slavery.[17]

After reading about Somersett's Case, Joseph Knight, an enslaved African who had been purchased by his master John Wedderburn in Jamaica and brought to Scotland, left him. Married and with a child, he filed a freedom suit, on the grounds that he could not be held as a slave in Great Britain. In the case of Knight v. Wedderburn (1778), Wedderburn said that Knight owed him "perpetual servitude". The Court of Sessions of Scotland ruled against him, saying that chattel slavery was not recognized under the law of Scotland, and slaves could seek court protection to leave a master or avoid being forcibly removed from Scotland to be returned to slavery in the colonies.[13]

But at the same time, legally mandated, hereditary slavery of Scots persons in Scotland had existed from 1606[18] and continued until 1799, when colliers and salters were emancipated by an act of the Parliament of Great Britain (39 Geo.III. c. 56). Skilled workers, they were restricted to a place and could be sold with the works. A prior law enacted in 1775 (15 Geo.III. c. 28) was intended to end what the act referred to as "a state of slavery and bondage,"[19] but that was ineffective, necessitating the 1799 act.

In 1783, an anti-slavery movement began among the British public to end slavery throughout the British Empire. In 1785, the English poet William Cowper wrote:

We have no slaves at home – Then why abroad? Slaves cannot breathe in England; if their lungs receive our air, that moment they are free, They touch our country, and their shackles fall. That's noble, and bespeaks a nation proud. And jealous of the blessing. Spread it then, And let it circulate through every vein.[20]

William Wilberforce (1759–1833), politician and philanthropist who was a leader of the movement to abolish the slave trade.

In the 1820s, the abolitionist movement revived to campaign against the institution of slavery itself. In 1823 the first Anti-Slavery Society was founded. Many of its members had previously campaigned against the slave trade. On August 28, 1833, the Slavery Abolition Act was given Royal Assent, which paved the way for the abolition of slavery throughout the British Empire, which was substantially achieved in 1838. In 1839, the British and Foreign Anti-Slavery Society was formed by Joseph Sturge, which attempted to outlaw slavery worldwide and also to pressure the government to help enforce the suppression of the slave trade by declaring slave traderspirates. The world's oldest international human rights organization, it continues today as Anti-Slavery International.[23]

In the principalities of Wallachia and Moldavia (both now part of Romania), the government held slavery of the Roma (often referred to as Gypsies) as legal at the beginning of the 19th century. The progressive pro-European and anti-Ottoman movement, which gradually gained power in the two principalities, also worked to abolish that slavery. Between 1843 and 1855, the principalities emancipated all of the 250,000 enslaved Roma people.[24]

Hugh Elliot was a noted abolitionist. Whilst Governor in the British West Indies, he was reported to be the driving force behind the arrest, trial and execution of a wealthy white planter Arthur Hodge for the murder of a slave.

With slaves escaping to New York and New England, legislation for gradual emancipation was passed in Upper Canada (1793) and Lower Canada (1803). In Upper Canada the Assembly ruled that no slaves could be imported; slaves already in the province would remain enslaved until death, no new slaves could be brought into Upper Canada, and children born to female slaves would be slaves but must be freed at age 25. In practice, some slavery continued until abolished in the entire British Empire in the 1830s.[36]

Uncle Tom's Cabin inflamed public opinion in the North and in Britain against the personified evils of slavery.

The historian James M. McPherson defines an abolitionist "as one who before the Civil War had agitated for the immediate, unconditional, and total abolition of slavery in the United States." He does not include antislavery activists such as Abraham Lincoln or the Republican Party, which called for the gradual ending of slavery.[37]

The first attempts to end slavery in the British/American colonies came from Thomas Jefferson and some of his contemporaries. Despite the fact that Jefferson was a lifelong slaveholder, he included strong anti-slavery language in the original draft of the Declaration of Independence, but other delegates took it out.[38]Benjamin Franklin, also a slaveholder for most of his life, was a leading member of the Pennsylvania Society for the Abolition of Slavery, the first recognized organization for abolitionists in the United States.[39] Following the Revolutionary War, Northern states abolished slavery, beginning with the 1777 constitution of Vermont, followed by Pennsylvania's gradual emancipation act in 1780. Other states with more of an economic interest in slaves, such as New York and New Jersey, also passed gradual emancipation laws, but by 1804, all the northern states had abolished it. Some slaves continued in servitude for two more decades but most were freed.

Also in the postwar years, individual slaveholders, particularly in the Upper South, manumitted slaves, sometimes in their wills. Many noted they had been moved by the revolutionary ideals of the equality of men. The number of free blacks as a proportion of the black population increased from less than one percent to nearly ten percent from 1790 to 1810 in the Upper South as a result of these actions.

As President, on March 2, 1807, Jefferson signed the Act Prohibiting Importation of Slaves and it took effect in 1808, which was the earliest allowed under the Constitution. In 1820 he privately supported the Missouri Compromise, believing it would help to end slavery.[38][40] He left the anti-slavery struggle to younger men after that.[41]

In the 1850s in the fifteen states constituting the American South, slavery was established legally. While it was fading away in the cities and border states, it remained strong in plantation areas that grew cotton for export, or sugar, tobacco or hemp. By the 1860 United States Census, the slave population in the United States had grown to four million.[42] American abolitionism was based in the North, and white Southerners alleged it fostered slave rebellion.

The Republican Party wanted to achieve the gradual extinction of slavery by market forces, for its members believed that free labor was superior to slave labor. Southern leaders said the Republican policy of blocking the expansion of slavery into the West made them second-class citizens, and challenged their autonomy. With the 1860 presidential victory of Abraham Lincoln, seven Deep South states whose economy was based on cotton and slavery decided to secede and form a new nation. The American Civil War broke out in April 1861 with the firing on Fort Sumter in South Carolina. When Lincoln called for troops to suppress the rebellion, four more slave states seceded.

Lincoln's Emancipation Proclamation was an executive order of the U.S. government issued on January 1, 1863. changing the legal status of 3 million slaves in designated areas of the Confederacy from "slave" to "free." Slaves were legally freed by the Proclamation and became actually free by escaping to federal lines, or by advances of federal troops. Many served the federal army as teamsters, cooks, laundresses and laborers. Plantation owners, realizing that emancipation would destroy their economic system, sometimes moved their slaves as far as possible out of reach of the Union army.[45] By "Juneteenth" (June 19, 1865, in Texas), the Union Army controlled all of the Confederacy and liberated all its slaves. The owners were never compensated.[46][47]

The border states were exempt from the Emancipation Proclamation, but they too (except Delaware) began their own emancipation programs.[48] When the Union Army entered Confederate areas, thousands of slaves escaped to freedom behind Union Army lines, and in 1863 many men started serving as the United States Colored Troops. The 13th Amendment to the U.S. Constitution took effect in December 1865 and finally ended slavery throughout the United States. It also abolished slavery among the Indian tribes, including the Alaska tribes that became part of the U.S. in 1867. [49]

The abolitionist movements and the abolition of slavery have been commemorated in different ways around the world in modern times. The United Nations General Assembly declared 2004 the International Year to Commemorate the Struggle against Slavery and its Abolition. This proclamation marked the bicentenary of the birth of the first black state, Haiti. Numerous exhibitions, events and research programmes were connected to the initiative.

2007 witnessed major exhibitions in British museums and galleries to mark the anniversary of the 1807 abolition act – 1807 Commemorated[50] 2008 marks the 201st anniversary of the Abolition of the Slave Trade in the British Empire.[51] It also marks the 175th anniversary of the Abolition of Slavery in the British Empire.[52]

The Faculty of Law at the University of Ottawa held a major international conference entitled, "Routes to Freedom: Reflections on the Bicentenary of the Abolition of the Slave Trade", from 14 to 16 March 2008.[53] Actor and human rights activist Danny Glover delivered the keynote speech announcing the creation of two major scholarships intended for University of Ottawa law students specializing in international law and social justice at the conference's gala dinner.

Brooklyn, New York has begun work on commemorating the abolitionist movement in New York.

No one shall be held in slavery or servitude; slavery and the slave trade shall be prohibited in all their forms.

Although outlawed in most countries, slavery is nonetheless practiced secretly in many parts of the world. Enslavement still takes place in the United States, Europe, and Latin America,[54] as well as parts of Africa, the Middle East, and South Asia.[55] There are an estimated 27 million victims of slavery worldwide.[56] In Mauritania alone, estimates are that up to 600,000 men, women and children, or 20% of the population, are enslaved. Many of them are used as bonded labour.[57]

In the United States, The Action Group to End Human Trafficking and Modern-Day Slavery is a coalition of NGOs, foundations and corporations working to develop a policy agenda for abolishing slavery and human trafficking. Since 1997, the United States Department of Justice has, through work with the Coalition of Immokalee Workers, prosecuted six individuals in Florida on charges of slavery in the agricultural industry. These prosecutions have led to freedom for over 1000 enslaved workers in the tomato and orange fields of South Florida. This is only one example of the contemporary fight against slavery worldwide. Slavery exists most widely in agricultural labor, apparel and sex industries, and service jobs in some regions.

In 2000, the United States passed the Victims of Trafficking and Violence Protection Act (TVPA) "to combat trafficking in persons, especially into the sex trade, slavery, and involuntary servitude."[58] The TVPA also "created new law enforcement tools to strengthen the prosecution and punishment of traffickers, making human trafficking a Federal crime with severe penalties."[59]

The United States Department of State publishes the annual Trafficking in Persons Report, identifying countries as either Tier 1, Tier 2, Tier 2 Watch List or Tier 3, depending upon three factors: "(1) The extent to which the country is a country of origin, transit, or destination for severe forms of trafficking; (2) The extent to which the government of the country does not comply with the TVPA's minimum standards including, in particular, the extent of the government's trafficking-related corruption; and (3) The resources and capabilities of the government to address and eliminate severe forms of trafficking in persons."[61]

^Rodney Stark, "For the Glory of God: How Monotheism Led to Reformations, Science, Witch-hunts, and the End of Slavery", p.322 [1] Note that there was typo in the original hardcover stating "31.2 percent"; this was corrected to 13.2% in the paperback edition and this can be verified using 1830 census data.